Field of the Invention
The present invention relates to a piezoelectric vibration piece and a piezoelectric vibrator.
Background Art
From the related art, in a mobile phone or a mobile information terminal device, a piezoelectric vibrator using crystal or the like has been generally adopted as a device used in a time source, a timing source of a control signal, a reference signal source, or the like. As such a piezoelectric vibrator, a piezoelectric vibrator has been known in which a piezoelectric vibration piece is hermetically sealed in a package having a cavity formed thereon.
As such a piezoelectric vibration piece, a piezoelectric vibration piece including a base portion, and a pair of vibration arms and support arms extending from the base portion has been known. In addition, a piezoelectric vibration piece is proposed in which a portion of the support arm on a base end side is formed in a tapered shape such that the width is gradually narrowed towards a tip end side, and a portion of the support arm on a tip end side is formed such that the width is broadened (refer to JP-A-2010-87574 described below).
In addition, a piezoelectric vibration piece is proposed in which a support arm includes a second linear portion which extends in parallel with an extension direction of a vibration arm from a base portion, a curved portion which is disposed to be connected to a tip end of the second linear portion and is formed to be curved, and a first linear portion which is disposed to be connected to a tip end of the curved portion and extends in parallel with the extension direction of the vibration arm (refer to JP-A-2009-118302 described below).
However, In the piezoelectric vibration piece disclosed in JP-A-2010-87574 described above, a step portion is formed in a boundary portion between the portion of the support arm on the tip end side which is formed broadly and the portion on the base end side which is formed in a tapered shape, and thus a so-called etching residue is easily generated in the step portion. For this reason, in the step portion, a crack occurs in the support arm, or the support arm is broken.
In addition, in the piezoelectric vibration piece disclosed in JP-A-2009-118302 described above, the support arm is formed to be curved, and thus an occurrence of a vibration leakage (a leakage of vibrational energy) to the package side from the piezoelectric vibration piece may not be reduced.
In addition, the width dimension of the support arm (the length of the pair of support arms in a separation direction) is constant, and thus it is not possible to sufficiently ensure a junction area of the first linear portion on a tip end side which is mounted in the package, and it is not possible to sufficiently obtain a mounting strength.